Hydraulic motor unit arrangement

ABSTRACT

A HYDRAULIC MOTOR UNIT CONSTITUTED BY THE ASSEMBLY OF THREE MAIN SUB-UNITS CONNECTED BY GENERALLY PLANE FACES. THE CENTRAL SUB-UNIT CONTAINING THE ROTOR IS DISPOSED BETWEEN THE DISC-BRAKE SUB-UNIT AND THE SUB-UNIT CONTAINING THE NON ROTAR PARTS OF THE SUPPLY AND EXHAUST SYSTEM.

Nov- 9, 1971 J. FAISANDIER 3,618,467

HYDRAULIC MOTOR UNIT ARRANGEMENT Filed June 5, 1969 4 Sheets-Sheet l in N m m H m I my q (\I Q5 y w 9. o N

Q q a 1 Nov. 9, 1971 J. FAISANDIER 3,618,467

HYDRAULIC MOTOR UNIT ARRANGEMENT Filed June 5, 1969 4, Sheets-Sheet 3 4 Sheets-Sheet 5 Filed June 3, 1969 Nov. 9, 1971 J. FAISANDIER 3,618,457

HYDRAULIC MOTOR UNIT ARRANGEMENT Filed June 5, 1969 4 Sheets-Sheet 4 FIG. 4

United States Patent Olhce 3,618,467 HYDRAULIC MOTOR UNIT ARRANGEMENT Jacques Faisandier, Chatillon-sous-Bagneux, France, as-

signor to Societe dApplications des Machines Motrices S.A., Issy les Moulineaux, France Filed June 3, 1969, Ser. No. 829,969 Claims priority, application France, June 6, 1968,

Int. Cl. F01b 25 04; Flfid 25/00 US. Cl. 91-1 8 Claims ABSTRACT OF THE DISCLOSURE A hydraulic motor unit constituted by the assembly of three main sub-units connected by generally plane faces. The central sub-unit containing the rotor is disposed between the disc-brake sub-unit and the sub-unit containing the non rotary parts of the supply and exhaust system.

FIELD OF THE INVENTION The present patent application relates to a hydraulic motor unit having a characteristic arrangement and providing machining, assembly, dismatling, and re-assembly facilities.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWING FIG. 1 shows a preferred embodiment of the motor unit as a whole in axial section, and the advantages of the present invention can readily be seen therefrom.

FIG. 2 is a functional diagram of the motor illustrated, FIG. 2 depecting FIG. 1 in an application which may for example comprise the rotational driving of a radar aerial wherein the invention has to provide for continuous rotation (search) and varied movements (starting stopping-readjustmentpursuit) while requiring only negligible power.

FIG. 3 illustrates an application of the motor shown in FIG. 1 wherein for reasons of natural frequency due to the compressibility of the oil, it is advantageous to place the servovalve as close as possible to the actual motor. The servovalve may advantageously be included in the engine unit or, as illustrated, the mounted directly on the latter and connected directly to the motor without the aid of pipes other than the bores in the body of the units.

FIG. 4 shows a functional diagram of the servovalve of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 the middle main block is designated by 1 and is in the form of a cylinder which is generally solid but which, on each face, is provided with coaxial cylindrical cavities. These cavities communicate with one another through their bottoms.

The main unit II is disposed under one of the faces of this cylinder 1 and is in the form of a sleeve the outer surface of which is cylindrical. The outlet diameters of 3,618,467 Patented Nov. 9, 1971 the two units 1 and II may be equal or slightly diflerent, as illustrated, in order to permit engagement of one in the other, the fastening being completed by a certain number of bolts, such as 12.

The unit II contains all the rotating parts, namely the rotor 13 of the so-called star type, radial-cylinder hydraulic motor. The cam (not shown) is constituted or carried by the internal surface of the sleeve. The distribution crown is fixed in rotation, and as this motor is entirely conventional it will not be further described.

The rotor 13 is integral in rotation with the driving shaft 15 by means of splines 16.

On the opposite face to that at which it is connected to the middle unit 1, the unit II is closed by the end plate VIII, which is held by the previously mentioned bolts 12.

The end plate 8 carries the bearing 17 of the drive shaft 15, which passes through the three units 1, II, and VIII.

The unscrewing of the bolts 12 thus gives complete accessibility to both faces of the rotor 13 of the motor, which can easily be separated from the shaft 15 and can be Withdrawn therefrom by extraction from right to left in the drawing.

On the second face of the middle unit 1 there is disposed the cylinder which constitutes the disc brake unit III, the brake being normally applied. This unit is fastened to the unit 1 by bolts, such as 18.

Finally, on the other face of the unit II there is disposed the casing VII which, in servo-motor applications, contains a tachogenerator and/or one or more synchro transmitters, or else a gyroscope. In the absence of these various appliances a simple end plate may be utilized.

In the cavity facing the unit II, the unit I contains the unit IV which, by means of the roller bearings 19, constitutes the second bearing unit for the shaft 15.

The unit I also contains the fixed part of the supply and exhaust system. In FIG. 1 only one of the two systems may be seen it being obvious that if the motor has n cylinders there will be n supply systems and n exhaust systems disposed alternately in a crown in relation to the geometrical axis of the motor. The system illustrated, which is designated generally by the reference numeral 20, is entirely known in the art and will not be further described.

In the other cavity facing the unit III, the unit I contains the brake assembly designated by V. The brake assembly comprises a cylindrical unit more particularly designated by 21, mounted on the shaft 15 by splines 22. The unit 21 comprises a convention disc brake including five rings interposed between six fixed rings.

The unit III is machined to receive the brake operating member 23, the brake spring 24, and the differential piston 25. Piston 25 is designed so that the control pressure admitted by the connection 26 effects the release of the brake. s

Against the unit III, on the opposite side to the brake assembly V, there is disposed the unit VI. Unit VI partly penetrates into unit III, the latter having been machined for this purpose. The shape of the penetrating portion combines with the shape of the piston 25, this penetrating portion constituting the bearing unit for the secondary shaft 27 which runs in the bearings 28.

According to one characteristic of the arrangement, the shaft 27 is engaged in the shaft 15, and the fastening is effected by splines 29.

The shaft 27 drives the tachogenerator 30 through the gear train 31 and 32 and the synchro transmitter 33 through the gears 34 and 35.

In applications where it is necessary to have two synchro transmitters, respectively for rough and precision adjustment, and in applications where it is necessary to have a gyrometer, the four devices including the tachogenerator are mounted in the unit VII and disposed in star form around the auxiliary shaft 27 which transmits the movement to them.

FIG. 2 illustrates the motor of FIG. 1, which is designated generally by 40, as driven by a variable pump 41.

In FIG. 2 the references used in FIG. 1 are again applied to the common parts shown in the diagram. The main shaft of the motor drives at 42 the power reducer (not illustrated), while the auxiliary shaft 27 is connected on the one hand to the synchro 33 giving the position, and on the other hand to the tachogenerator 30 giving an electric signal proportional to the driving speed.

The synchro receiver 33 for the position drive is illustrated diagrammatically by its rotor 33 and is represented symbolically as a whole at 33". The synchro transmitter to which receiver 33 is connected is indicated at 43.

When it is desired to control load position, the synchro is connected by the relay 44, which is placed at Po." Any error in relative position between the synchro receiver 33 and the synchro transmitter 43 is translated into an electric signal which, suitably amplified at 45 with demodulation and possibly correction by an electric filter network at 46 and re-amplification at 47, acts on the torque motor 48 of the servo valve 49. Valve 49 controls the actuator 50, which in turn controls the delivery of the pump 41, thereby angularly displacing the hydraulic motor 40 until coincidence of the relative positions of the two synchros is achieved.

The receiver synchro is generally mounted on the driven device, downstream of the power reducer, but such a mounting introduces play and elasticity which may set up vibrations whereby the servomechanism is excited with delay. Consequently, it has previously been necessary to reduce the amplification of the servo-mechanism circuit, thereby reducing its degree of precision.

The auxiliary reducer 34, between the motor and the synchro 33, having no power to transmit, is not subject to wear and therefore does not give rise to play.

The direct mounting of the receiver synchro on the auxiliary output shaft 27 must therefore be considered as one of the features of the present invention.

When it is desired to control speed, the tachogenerator 30, which is driven by the secondary shaft of the hydraulic motor. is placed in opposition with an electric voltage supplied by the potentiometer 50, Potentiometer 50 selects the desired speed and the relay 44 is switched to the position Vi and the filter 46 is replaced in the circuit filter 46" when. speed control is desired.

FIG. 3 shows again the motor illustrated in FIG. I; only the units I and IV, the drive shaft 15, and the auxiliary shaft 27 being depicted in FIG. 3. The rough adjustment receiver synchro 51 and the precision adjustment receiver synchro 52 are mounted on shaft 27; the tachogenerator not being visible in the figure.

In FIG. 3 the unit IX, which represents the servovalve and servovalve drive assembly, is not included in unit I, as would be preferably. In the sake of clarity in the drawing, unit 14 has been shown at the side of unit I thereby eliminating all intermediate free piping, communicattion being solely through bores in the units I and IX.

In FIG. 3 only the body of the servovalve, the casing 61 containing the torque motor and its electrical equipment, and the plug socket 62 with its pins are indicated.

The functional diagram of the FIG. 3 arrangement is shown in FIG. 4. In FIG. 4 the hydraulic motor 40 illustrated in FIG. 3 is shown in connection with its servovalve 60 together with the position remote control device.

The servovalve 60 may be a conventional slide valve distributor with three lands, with pressure inlet at P, the ports U and U each alternately effecting supply and exhaust to and from the motor, and two ports R leading to the tank. The slide valve is controlled by the rotary distributor 63, which is mounted on the same shaft as the torque motor 64, the tachometer element 65, and the position discriminator 66.

This assembly effects the servocontrol and stabilisation of the servomechanism.

The rotor of the torque motor 64 is a permanent magnet mounted in an armature applying a field perpendicular to its mean position. The production of this field results from the passing of a direct current in a winding carried by the armature.

The tachometer element 65 is constituted by an element identical to the motor element but of smaller thickness tachometer 65 supplies a voltage proportional to the speed of rotation of shaft 27. The position discriminator 66 is constituted mainly by an inductive potentiometer mounted directly on the shaft of the motor element.

The mounting of the three elements 64, 65 and 66 on the same shaft eliminates all play and elasticity between the elements and facilitates the very compact mounting of the whole arrangement, while providing better stability and greater accuracy of the servomechanism enhanced accuracy results because the damping signals thus produced are more perfect than if they were obtained in other stages or through the medium of transmissions involving play or elasticity.

A rotary induction potentiometer 67 indicates the movement of the slide of the valve 60.

The voltages supplied by the elements '65, 66, 67 are damping voltages which are supplied to the amplifier 68 which controls the torque motor 63.

The whole arrangement which has just been described is moreover well known and has already been described by the present inventor in earlier patents, which have already been published.

On the other hand, a new point in the present arrangement consists in that, instead of receiving directly a control voltage supplied by a potentiometer, the amplifier 68 receives the error signal resulting from the difference in position between the transmitter synchro 43 and the receiver synchro 33.

The direct fastening of the servovalve 60 on the motor 4-0 effects maximum reduction of the volume of oil between the motor and the servovalve. This, in turn, permits the highest possible natural frequency for a given motor and inertia; thus making it possible to obtain the best possible static and dynamic precision.

Returning to a consideration of FIG. 2, there will be now be described the circuit which controls the braking of the motor 40; the brake having been described in connection with FIG. 1.

The pressure necessary for releasing the brake, for example 6 bars, is normally provided by the gear pump 70. Pump 70 also feeds the servovalve 49 and may be keyed on the shaft controlling the pump 41. In the event of the failure or intentional stopping of the pump 70, brake release pressure may be supplied by the emergency hand pump 71 an automatic hydraulic switch 72 isolates the normal and emergency circuits. The brake release pressure is delivered to the connection 26 of the motor unit (FIG. 1).

The two pumps 70 and '71 apply suction to the leakage return tank 73. The reference 75 designates a filter and the reference 74 a safety valve.

In the general circuit the safety valve 76 and pressure balancing means 77 will be noted.

It will be observed that for the sake of simplification of the drawing, FIG. 4 illustrates only a single receiver synchro 33, whereas FIG. 3 includes a rough adjustment receiver synchro and a precision adjustment receiver synchro. The replacement of one device by the other is standard practice.

According to another characteristic of the invention the tachogenerator 30, combined with the transmitter synchro 33 and 43, advantageously replaces the anticipation dynamo driven by the control station. This dynamo entails the disadvantage of requiring a substantial force from the control station and supplementary conductors. The transmitter synchros give the difference ES of the voltage corresponding to the input and output movements. By electrical differentiation obtained by a conventional resistor-capacitor circuit (not illustrated) we obtain DE/dt-DS/dt, the dynamo 30 gives DS/dt, and thus by summation we shall obtain DE/dt, which is of course the voltage which in the usual circuit is given by the anticipation dynamo. Another embodiment of the invention will now be described, which will take into account the possible presence of a gyrosope in the casing VII, as already mentioned.

In the case of turret stabilisation, that is to say a system which keeps a turret in a fixed position independent of the support position (armoured fiighting vehicle, boat, aircraft) and which makes it possible to control the same as if the support were fixed, it is advantageous to know through use of a gyroscope the absolute speed of angular displacement of the carrier vehicle.

If the gyroscope is mounted on the carrier vehicle, it is necessary to install rather long electric cables and, for lateral laying, to use a rotating contact between the turret and the gyroscope.

It is therefore advantageous to reproduce, in the turret a plane of reference which itself remains parallel regardless of the direction of the carrier vehicle.

According to the invention the foregoing is achieved by finding the desired plane by suitable reduction, in the casing VII of the receiver synchros, and the gyroscope is made fast to said plane.

It will be observed that a rotating contact is nevertheless necessary, but this is much easier to achieve than the contact between turret and gyroscope which connect large parts of the turret.

For this application a tacheogenerator giving the relative speed of the turret is disposed in the casing VII together with the gyroscope and the receiver synchro or synchros.

I claim:

1. A hydraulic motor assembly comprising:

a first subassembly, said first subassembly defining a first housing having an axis and a pair of oppositely disposed plane faces extending perpendicularly to said axis, said first housing further being provided with a bore co-axial with said axis extending therethrough;

a second subassembly having the same external shape as said first subassembly, said second subassembly defining a second housing having an axis and a pair of oppositely disposed plane faces extending perpendicularly thereto, said second housing defining supply and exhaust ports for motor driving fluid, said second housing having a bore so-axial with said axis extending therethrough;

a third subassembly having the same external shape as said first and second subassemblies, said third subassembly defining a third housing having an axis and a pair of plane faces extending perpendicularly thereto, said third housing also having a bore co-axial with said axis extending therethrough;

means for mounting said subassemblies with their axes in aligned relationship;

drive shaft means mounted for rotation on said aligned axes;

a fluid driven rotor mounted within said first housing for rotation with said drive shaft means; and

brake means mounted within the bore of said third housing and in operation relationship to said drive shaft means.

2. The apparatus of claim 1 wherein said drive shaft means comprises:

a plurality of axles; and

means coupling said axles to one another, said coupling means permitting disassembly of said drive shaft means by translational movement.

3. The apparatus of claim 1 further comprising:

a fourth subassembly having the same exterior shape as said first subassembly, said fourth subassembly defining a fourth housing having an axis and a plane face extending perpendicularly thereto, said fourth housing also having an opening;

means for mounting said fourth subassembly in axially aligned relationship to said first, second and third subassemblies;

,a synchro-comparator mounted in the opening in said fourth housing;

a tachometer mounted in the opening in said fourth housing; and

means coupling said comparator and tachometer to said drive shaft means.

4. The apparatus of claim 2 further comprising:

a fourth subassembly having the same exterior shape as said first subassembly, said fourth subassembly defining a fourth housing having an axis and a plane face extending perpendicularly thereto, said fourth housing also having an opening;

means for mounting said fourth subassembly in axially aligned relationship to said first, second and third subassemblies;

a synchro-comparator mounted in the opening in said fourth housing;

a tachometer mounted in the opening in said fourth housing; and

means coupling said comparator and tachometer to said drive shaft means.

5. The apparatus of claim 3 further comprising:

a gyroscope mounted in said fourth housing.

6. The apparatus of claim 4 further comprising:

a gyroscope mounted in said fourth housing.

7. The apparatus of claim 3 wherein said fourth subassembly comprises a closed face at the end opposite to said plane face.

8. The apparatus of claim 4 wherein said fourth subassembly comprises a closed face at the end opposite to said plane face.

References Cited UNITED STATES PATENTS 1,616,841 2/1927 Beebe 6052 2,163,079 6/1939 Benedek 6053 B 2,186,409 1/ 1940 Ferris 6053 2,416,801 3/1947 Robinson 6053 W 3,214,911 11/1965 Kempson 6053 US. Cl. X.R.

3,241,320 3/1966 Roberts 6053 D EDGAR W. GEOGHEGAN, Primary Examiner 

